PZT Plate Research Articles

Thickness effects on magnetoelectric coupling for Metglas/PZT/Metglas laminates

Thickness effects on the ME coefficient αME and electromechanical resonance frequency of Metglas/PZT/Metglas tri-layered laminates are investigated. The thickness of the magnetic plate is changed by assembling different numbers of the Metglas thin sheets (30 μm for each layer) while the PZT plate is maintained at constant thickness (0.5 mm). At 1 kHz of the applied alternating magnetic field, only one peak presents in the ME coefficient (αME) versus static magnetic field (HS) curve. As the thickness ratio n increases, the peak value of μME first increases and reaches a maximum at approximately n = 0.519, and then decreases afterward. The peak position (Hoptim) moves steadily toward a higher value as n increases. It is suggested that the relaxation factor k of the magnetic phase is reduced as n increases, causing the decrease of the piezomagnetic coefficient d11,m and the increase of Hoptim. By employing the micromechanics model and considering the degradation of d11,m with n, an optimized thickness ratio of 0.5 is predicted, which is in agreement with the experimental observations. The resonance frequency of the laminate increases with n, which is consistent with the calculation using a straightforward mixture law.

1P1-A02 マイクロリアクタ技術と圧電振動子を利用したエマルション生成デバイスの開発(岡山発のロボティクス・メカトロニクス技術と産学官連携)

The aim of this paper is to introduce a project for emulsion generation device in Okayama University. We have generated sub-micrometer size droplets by using an ultrasonic vibration and microchannel plates. Especially, the device and system is for the generation of drug droplets. The ultrasonic vibration is oscillated by PZT plates and microchannel plates are made of stainless steel. The distribution of pressure depends on cross sectional pattern of the microchannel. As the applied voltage increased, emulsion became smaller and distribution became sharper. When the vibrator was oscillated in 2.25 MHz, the generated emulsion has an average diameter of 200 nm.

Nondestructive Evaluation of Polarization in LTCC/PZT Piezoelectric Modules by Thermal Wave Methods

This work investigates the polarization behavior of low-temperature cofired ceramic (LTCC)/PZT sensor-actuator-modules fabricated by packaging of ceramic PZT plates between alumosilicate-corundum LTCC green layers and subsequent sintering at elevated temperatures. Polarization evaluation was done by applying the laser intensity modulation method (LIMM) where a thermal wave travelling into the ferroelectric PZT ceramic plate is generated by an intensity-modulated laser beam. The penetration depth of the thermal wave was varied with the modulation frequency allowing the separation of pyroelectric response contributions at different regions from the surface to the frequency-dependent penetration depth of the thermal wave.

A novel frequency multiplier based on magnetoelectric laminate

We report a novel frequency multiplier based on the magnetoelectric (ME) effect in a simple multiferroic laminate, made up of an amorphous FeBSiC magnetic layer bonded onto a Pb(Zr,Ti)O 3 plate wrapped with a coil. By applying an input signal with a frequency f to the coil, an output signal with 2 f can be generated from the PZT plate due to the ME coupling. This ME laminate-based device can be operated in a broad frequency range and switched by a low bias magnetic field, offering potential opportunities for frequency multipliers in electrical applications.

Possibility of controlling the relation between the shear and flexure energies during the vibration of a thin shear piezoelectric plate by changing the electrode shape

Electrode modifications are proposed for a shear piezoelectric PZT plate in order to change the relation between the energies of the components of the total flexure—shear mode. To this end, surface flexures are visualized using holographic interferometry and the measurement of the amplitude-frequency characteristics. Simple model concepts are suggested for the total mode.

Low-frequency magnetoelectric effect in a Galfenol-PZT planar composite structure

The forward and inverse magnetoelectric (ME) effects are experimentally studied in a two-layer planar structure containing mechanically coupled Galfenol and PZT plates. The process of production of polycrystalline Galfenol plates and their magnetic and magnetostriction characteristics are described. For the forward ME conversion, the dependences of the amplitude of the voltage generated by the structure on the magnitude and orientation of a dc magnetic field and the frequency and amplitude of a modulating magnetic field are measured. For the inverse ME conversion, the dependences of the amplitude of the change in the magnetic induction of the structure on the dc magnetic field and the frequency of an ac electric field applied to the structure are measured. The efficiencies of the forward and inverse ME conversion are estimated for the case of low-frequency field modulation and under conditions of the resonance excitation of bending and longitudinal mechanical vibrations in the structure.

Magnetoelectric effects in piezoelectric/soft magnetic amorphous FeCo-based ribbon composites

Magnetoelectric effect has been investigated in several multiferroic laminates generated by inserting a lead-zirconate titanate PZT plate between sheets of highly soft magnetic amorphous FeCo-based alloy ribbon. The results show that the magnetoelectric coefficient αE (= dE/dH) depends on the rest glass-forming elements as well as the concentration of Co substitution. Giant magnetoelectric is found for the composite of Fe73.5Cu1Nb3B9Si13.5 ribbon, where αE as high as 1000 mV/cmOe at low field of 50 Oe. aE can be further improved up to 1170 mV/cmOe at 20% Fe substituted by Co. The higher the Co concentration, the lower magnetoelectric effect is observed. High magnetoelectricty at low field makes these composites suitable for special applications such as smart sensors for detecting microtesla magnetic fields and especially biosensor for magnetic label detection.

Analysis and measurement of lateral elliptic motion effect for an asymmetric disc-type ultrasonic motor

This paper presents an analysis and measurement method for studying lateral elliptic motion effect of an asymmetric disc-type ultrasonic motor whose stator is a circular disc with a bonded PZT plate serving as a drive. At the edge of the stator with a simple, fixed three-point support of a 120°–90°–150° configuration, there exists a coupled vibration wave with lateral elliptical motion so as to generate a driving force between the stator and the rotor. The equations of the lateral elliptic motion and the driving force are analytically formulated based on the wave equation on the circular plate, thereby obtaining the driving frequency and the revolution speed of the motor. The relationship between the ultrasonic stator and its boundary condition is investigated as well. The analysis shows that the circumferential edge with a 90° included angle is an optimal contact section for the placement of the rotor. Experiments using the laser vibrometer and photodetector are used to show the validity of the proposed analysis method.

Thin film magnetoelectric composites near spin reorientation transition

We report the use of a magnetic instability of the spin reorientation transition type to enhance the magnetoelectric sensitivity in magnetostrictive–piezoelectric structures. We present the theoretical study of a clamped beam resonant actuator composed of a piezoelectric element on a passive substrate actuated by a magnetostrictive nanostructured layer. The experiments were made on a polished 150 μm thick 18×3 mm 2 lead zirconate titanate (PZT) plate glued to a 50 μm thick silicon plate and coated with a giant magnetostrictive nanostructured Nx(TbCo 2 5nm/FeCo 5nm) layer. A second set of experiments was done with magnetostrictive layer deposited on PZT plate. Finally, a film/film structure using magnetostrictive and aluminium nitride films on silicon substrate was realized, and showed ME amplitudes reaching 30 V Oe −1 cm −1. Results agree with analytical theory.

Fabrication of Micro Accelerometer Using Screen Printed BaTiO3 Film on a Ceramic Substrate and Its Characterization

The concept of MEMS sensors directly fabricated on a ceramic substrate, which can be used for a package of end product, was proposed. As one of such sensors, a micro accelerometer utilizing a fringe capacitance formed in a ferroelectric material was focused on. For this sensor, in stead of a previously used bulk PZT plate, a screen-printed BaTiO3 (BTO) film on a ceramic alumina substrate was herein employed. A screen-printing method can save the amount of raw material of the film, because a comparatively thick film can be deposited only on a specified area. Moreover, BTO does not contain harmful lead material. The optimal condition for fabricating a BTO film on an alumina substrate with minimum unwanted surface defects was experimentally searched. The number of defects was decreased by employing a metal barrier of Pt layer underneath BTO, and by setting the annealing temperature for crystallization to a higher value of 1,400°C. A comparatively high relative dielectric constant of er =926 was achieved. An accelerometer using a BTO film was practically fabricated. The sensitivity of it was estimated as 0.1 pF/g, which is degraded a little compare with the previously developed accelerometer using a PZT plate; however, the order is same.

Design and Performance Evaluation of Mini-Lightweight Piezo-Composite Actuators

In this paper, through an evaluation process conducted on several designs of mini-LIPCA (Lightweight Piezo-Composite curved Actuator), an optimal design of a mini-LIPCA has been proposed. Comparing with the LIPCA-C2, the design of the mini-LIPCA comes with reduced overall size and a thinner active layer. Since a variation in the number and lay-up of fiber composite layers may strongly affect the performance of the device, one is able to configure several designs of mini-LIPCA. The evaluation process is then followed in order to determine a configuration which characterizes the possibly optimal performance. That is, a design of a mini-LIPCA is said to be optimal if it is capable of producing a maximum out-of-plane displacement. The size of the LIPCA to be investigated was selected to be 10 mm × 20 mm in which the thickness of PZT plate is about 0.1 mm. The thickness of glass/epoxy and carbon/epoxy are about 0.09 mm and 0.1 mm, respectively. The evaluation process has been conducted thoroughly, i.e., analytical estimation, numerical approximation and the experimental measurement are all involved. Firstly, the design equation was used to calculate essential parameters of proposed lay-up configurations. Secondly, ANSYS, a commercial FEA package, was utilized to estimate displacement outputs of the actuators upon being excited. Finally, experimental measurements were able to verify the predicted results.

Acoustic wave transmission through piezoelectric structured materials

This paper deals with the transmission of acoustic waves through multilayered piezoelectric materials. It is modeled in an octet formalism via the hybrid matrix of the structure. The theoretical evolution with the angle and frequency of the transmission coefficients of ultrasonic plane waves propagating through a partially depoled PZT plate is compared to finite element calculations showing that both methods are in very good agreement. The model is then used to study a periodic stack of 0.65PMN-0.35PT/0.90PMN-0.10PT layers. The transmission spectra are interpreted in terms of a dispersive behavior of the critical angles of longitudinal and transverse waves, and band gap structures are analysed. Transmission measurements confirm the theoretical calculations and deliver an experimental validation of the model.

An investigation of vibration-induced protein desorption mechanism using a micromachined membrane and PZT plate

A micromachined vibrating membrane is used to remove adsorbed proteins on a surface. A lead zirconate titanate (PZT) composite (3 x 1 x 0.5 mm) is attached to a silicon membrane (2,000 x 500 x 3 microm) and vibrates in a flexural plate wave (FPW) mode with wavelength of 4,000/3 microm at a resonant frequency of 308 kHz. The surface charge on the membrane and fluid shear stress contribute in minimizing the protein adsorption on the SiO(2) surface. In vitro characterization shows that 57 +/- 10% of the adsorbed bovine serum albumin (BSA), 47 +/- 13% of the immunoglobulin G (IgG), and 55.3~59.2 +/- 8% of the proteins from blood plasma are effectively removed from the vibrating surface. A simulation study of the vibration-frequency spectrum and vibrating amplitude distribution matches well with the experimental data. Potentially, a microelectromechanical system (MEMS)-based vibrating membrane could be the tool to minimize biofouling of in vivo MEMS devices.

Flow characterization of valveless micropump using driving equivalent moment: theory and experiments

A valveless micropump, actuated by a PZT disk bonded to a glass plate, can generate positive flow. In order to estimate flow characteristics of micropumps, it is necessary to theoretically analyze the radial expansion (more specifically, the equivalent moment) of the PZT disk according to the voltage input. Using the equivalent moment, deflection equations are derived for the tri-layer disk (PZT, epoxy bonder and glass plate) and are confirmed to match well with experiments. The flow rate of the valveless micropump is also theoretically and experimentally investigated in terms of input voltage and oscillation frequency. The flow increased at a rate of 0.1 μL/min/V, and the maximum flow rate was obtained at the driving frequency of around 225 Hz.

Shape Control in Composite Laminates Using Piezoelectric Actuators considering Thermal Deformation

Based on the first order shear deformation plate theory, a numerical analysis model of composite laminated plates with distributed PZT actuators under thermal load was established, and the corresponding formulae of finite element method were presented considering the effect of adhesive layer between PZT actuator and plate. For a two ends simply supported plate, the thermal deformation of the plates induced by different temperatures on the upper and lower surfaces and the thermal deformation compensation for the plates using PZT actuators were studied, then the optimization of voltages applied to each actuator was discussed.

Vibration Control of Piezoelectric Actuator by Implementation of Optical Positioning Sensor

PZT bimorph actuator is used to design mini-sized vibratory feeder applied in the micro-medical industry. Since the vibration trajectory of PZT bimorph actuator will be controlled to obtain desired parts feeding, optical positioning sensor is used to provide non-contact measurement with precise displacement. Because the torsional vibration causes the rotary motion of the actuator, the angle between the optical sensor and the PZT plate is subjected to change during the vibration procedure. Optical loss due to a varying reflection angle is compensated by multiple-segment micrometer calibration. Satisfactory hysteresis suppression and good waveform tracking is obtained with implementation of optical sensor in piezo-actuating system.

A stator for a self-running, ultrasonically-levitated sliding stage

Here we propose a self-running, ultrasonically-levitated sliding stage and investigate the levitation and propulsion characteristics of its stator. The stator consists of two aluminum beams and four PZT plates, which have two-paired bimorph configurations. A flexural standing wave was generated along the beam by applying an input voltage to the PZTs, and the stator could be levitated from a flat substrate by the acoustic radiation force generated by its own vibrating beam. The size of the stator was optimized using finite-element analysis (FEA) to maximize the vibration displacement amplitude of the beam. The flexural vibration modes at 24.3 and 102 kHz were the most prominent vibration modes having large displacement amplitudes. The stator was levitated at 23.2 and 96.1 kHz, which are close to the frequencies predicted by the FEA results. A standing wave was observed along the beam. The experimental and the simulated results showed good agreement. The levitation distance h was measured by varying the vibration displacement amplitude of the beam u, and was found to be proportional to u. When a traveling wave was excited along the beam by controlling the temporal phase difference of the two transducers, the stator could be made to hover and to move in the opposite direction to the traveling wave. The stator moved in the positive direction when the phase difference was in the ranges 0 degrees to 200 degrees and 310 degrees to 360 degrees, and in the negative direction when the phase difference was between 220 degrees and 260 degrees.

파형 및 주파수해석에 근거한 굽힘 압전 복합재료 작동기 손상모드의 비파괴적 평가

In this study, various damage modes in bending unimorph piezoelectric composite actuators with a thin sandwiched PZT plate during bending fracture tests have been evaluated by monitoring acoustic emission (AE) signals in terms of waveform and peak frequency as well as AE parameters. Three kinds of actuator specimens consisting of woven fabric fiber skin layers and a PZT ceramic core layer are loaded with a roller and an AE activity from the specimen is monitored during the entire loading using an AE transducer mounted on the specimen. AE characteristics from a monolithic PZT ceramic with a thickness of 250 ㎛ are examined first in order to distinguish different AE signals from various possible damage modes in piezoelectric composite actuators. Post-failure observations and stress analyses in the respective layers of the specimens are conducted to identify particular features in the acoustic emission signal that correspond to specific types of damage modes. As a result, the signal classification based on waveform and peak frequency analyses successfully describes the failure process of the bending piezoelectric composite actuator exhibiting diverse failure mechanisms. Furthermore, it is elucidated that when the PZT ceramic embedded actuators are loaded mechanical bending loads, the failure process of actuator specimens with different lay-up configurations is almost same irrespective of their lay-up configurations.

굽힘 압전 복합재료 작동기의 하중 특성

This article describes the load capability of bending piezoelectric actuators with a thin sandwiched PZT plate in association with the stored elastic energy induced by an increased dome height after a curing process. The stored elastic energy within the actuators is obtained via a flexural mechanical bending test. The load capability is evaluated indirectly in terms of an actuating displacement with a load of mass at simply supported and fixed-free boundary conditions. Additionally, a free displacement under no load of mass is measured for a comparison with an actuating displacement. The results reveal that an actuator with a top layer having a high elastic modulus and a low coefficient of thermal expansion exhibits a better performance than the rest of actuators in terms of free displacement as well as actuating displacement due to the formation of the large stored elastic energy within the actuator system. When actuators are excited at AC voltage, the actuating displacement is rather higher than the free displacement for the same actuating conditions. In addition, the effect of PZT ceramic softening results in a slight reduction in the resonance frequency of each actuator as the applied electric field increases. It is thus suggested that the static and dynamic actuating characteristics of bending piezoelectric composite actuators with a thin sandwiched PZT plate should be simultaneously considered in controlling the performance.

Identification of failure mechanisms in a smart composite actuator with a thin sandwichedPZT plate based on waveform and primary frequency analyses

In the present work, the monitoring of an acoustic emission (AE) activity has beenemployed to investigate the failure mechanisms of smart piezoelectric composite actuatorswith a thin sandwiched PZT plate during bending fracture tests. Three kinds of specimensconsisting of woven fabric fiber skin layers and a PZT ceramic core layer are loaded with aroller and the AE activity is monitored in real time during the entire loading by using aresonant type AE transducer mounted on the specimen. Post-failure observationsare conducted to identify particular features in the acoustic emission signal thatcorrespond to specific types of failure events. AE characteristics from monolithic PZTceramic are first examined to distinguish different AE signals from various possiblefailure mechanisms in the smart piezoelectric composite actuators. AE signalsare analyzed in terms of AE event count and AE cumulative energy, and areclassified into four different signal types based on the waveform and the primaryfrequency which is obtained by a short time Fourier transform (STFT). As aresult, the behavior of the four classified different AE signal types according to thewaveform and the primary frequency successfully describes the failure process of thesmart piezoelectric composite actuator with a thin sandwiched PZT plate showingvarious and multiple failure mechanisms. Finally, it is elucidated that each classifiedsignal type is related to the specific failure mechanism within the smart compositeactuator, and the AE characteristics are summarized in table 1, in association withthe individual failure mechanism of the smart piezoelectric composite actuator.